As the power of processing devices exponentially increases, high bandwidth communication links interconnecting these processing devices are increasingly important. Optical media or carriers are capable of providing such high bandwidth communication links. An on-die optical interconnect system may include a detector, a modulator, and an optical waveguide all manufactured and embedded within a single semiconductor die. Often, the semiconductor die is a silicon die, which may include both optical and electrical circuit components integrated therein. However, laser sources for providing the optical energy utilized and manipulated by the integrated silicon optical components are often not fabricated of silicon and therefore not integrated onto the silicon die.
Typical external laser sources include gallium arsenide based laser sources, which are chemically not compatible for integration with silicon. As such, these laser sources are externally coupled to the silicon die containing the optical components. To achieve a reasonable optical coupling, the laser source must be carefully aligned with the on-die optical components. The low error tolerances for alignment make this external coupling incompatible with high volume manufacturing (“HVM”).
One conventional technique used to couple an external laser source to on-die optical components is referred to as fiber pigtail coupling. Fiber pigtail coupling includes extra processing steps to etch a V-groove having a vertical termination that is optically transparent into the surface of the die. An optical fiber is subsequently placed into the V-groove with its end butt connected to the optically transparent vertical termination. The V-groove consumes a relative large amount of on-die real estate and the process of positioning the optical fiber into the V-groove does not lend itself well to HVM.